A device for the treatment of periodontal disease. The device includes a handle that has a configuration familiar to dental professionals and a cartridge that is locked into the handle when use, typically delivery of a composition to a periodontal pocket, is desired. The cartridge provides for effective delivery of compositions, such as agents, as its tip is deformable, typically from a circular to an oval shape so as to flatten. The deformation may be made either manually, by the dental professional, or upon contact with teeth or other tissues, whereby this flattened tip can penetrate deeply into periodontal pockets for quick and direct application of the composition, for example, therapeutic agents.